Maternal MTNR1B Genotype, Maternal Gestational Weight Gain, and Childhood Obesity

BACKGROUND: Maternal metabolic abnormalities have been related to offspring obesity especially during childhood. OBJECTIVES: We analyzed whether the gestational diabetes mellitus (GDM)-associated melatonin receptor 1B (MTNR1B) genotype of mothers modified the relation between maternal gestational weight gain and childhood obesity. METHODS: A total of 1114 Chinese mother-child pairs (mothers with or without prior GDM) were included. Mothers' MTNR1B rs10830962 genotype and gestational weight gain were assessed. Indicators of childhood obesity included BMI-for-age z-score, weight-for-age z-score, waist circumference, and body fat. Childhood overweight and obesity were also analyzed. RESULTS: We found that the maternal MTNR1B genotype significantly interacted with gestational weight gain on indicators of offspring's obesity (all P for interaction < 0.05). After multivariable adjustment, BMI-for-age z-scores associated with 1-kg gestational weight gain were 0.009 (SE 0.018), 0.026 (SE 0.010), and 0.061 (SE 0.010) in children with the maternal MTNR1B genotype CC, CG, and GG, respectively (P-interaction = 0.012). Similar interactions were observed for weight-for-age z-score, waist circumference, and body fat (P-interaction = 0.001, 0.003, and 0.012, respectively). The associations remained consistently significant in women with and without GDM. We also found significant interactions between the maternal MTNR1B genotype and gestational weight gain on the offspring's childhood overweight and obesity (P-interaction = 0.005 and 0.026, respectively). CONCLUSIONS: The maternal MTNR1B genotype might interact with gestational weight gain on offspring's obesity risk during childhood.